You are supposed to use /var/home/user instead of /home/user in your paths, scripts, etc (or /var/$HOME). Im not certain on the why but iirc its because on immutable systems only /var is writable so anything writable has to be under it.

Id say just recommend Photon. It works well on both mobile and desktop. I love voyager but two very different uis is going to confuse new users.

It depends. On older devices there isn’t much testing of newer versions of the kernel so they can be more broken than older version.

Case in point, recently on an old laptop (~12 years) I noticed video performance was really bad which I later found out was due to modern distros defaulting to the iHD intel graphics driver. But iHD is only supported from 5th gen (Broadwell) onward. So, on older devices anything depending on the graphics driver for hardware acceleration (like video decode) fails and falls back to software rendering.

Delta chat is based on top of email (i.e.SMTP, IMAP) so its like sending emails but in a chat format and encryption on top (and some more stuff).